1. Field of the Invention
The present invention relates to a control technique of controlling a process for a storage device in a network in transferring data to the storage device via a remote access server.
2. Description of the Related Art
Conventionally, an image capturing apparatus such as a digital camera or a digital video camcorder is connected to a network directly or via an adapter to upload image or video data stored in the image capturing apparatus to a server apparatus in the network. This process ensures a free space in the storage device of the image capturing apparatus.
A proposal about such a data upload process is described in, for example, Japanese Patent Laid-Open No. 2000-232599. According to Japanese Patent Laid-Open No. 2000-232599 (U.S. patent application Ser. No. 09/213,314), when a digital camera or an adapter detects connection to a network, communication connection to a transfer destination system is established via the network, thereby implementing automatic image data transfer to the transfer destination. This technique automatically ensures a free space in the storage device of the digital camera.
On the other hand, a recent home network often includes a router and makes a firewall function work on it to prevent viruses and unauthorized access from the Internet. The firewall function improves the security of the network but also makes it difficult for the network user to externally access a device in the network via the Internet. To enable external data transmission/reception, normally, a remote access server is arranged in the network.
Various proposals have been made so far for the process of externally uploading data to the server apparatus in the network using the remote access server.
For example, Japanese Patent Laid-Open No. 2003-233548 discloses a network system which implements, in the data upload process, upload by proxy transfer using a network switch and a proxy server arranged between a transfer source computer and a transfer destination computer.
According to Japanese Patent Laid-Open No. 2003-233548, the network switch has a monitoring means for monitoring traffic and detecting upload traffic as an upload target. The proxy server has an analyzing means for extracting the information of the transfer destination computer from the upload traffic, and a proxy reception means for receiving a file on behalf of the transfer destination computer. The proxy server also has a proxy transmission means for transmitting the received file to the transfer destination computer on behalf of the transfer source computer. With this arrangement, the network system can cause the proxy server to execute the upload process even when upload traffic has occurred.
Various proposals have also been made concerning the functions on the server apparatus side in the upload process.
For example, Japanese Patent Laid-Open No. 2005-100220 discloses an arrangement in which when providing a service in response to a request from a client, a server apparatus calculates the resource occupation value of each service based on the resource load value of the resource included in the server apparatus and the priority order of each client. According to this reference, it is possible to cause the server apparatus to execute a preset process for each service based on the result of comparison between the calculated resource occupation value and a predetermined threshold value.
However, the arrangement disclosed in Japanese Patent Laid-Open No. 2000-232599 does not consider the process load on the server apparatus side in executing the upload process.
Hence, in Japanese Patent Laid-Open No. 2000-232599, for example, if the load on the server apparatus side has already reached the performance limit before transferring upload data to it, data transfer may fail. Even when data transfer has succeeded, the processes of other devices connected to the server apparatus are held over. As a result, if a television (TV) tuner connected to the server apparatus is writing TV record data in it, the write of TV record data fails.
Similarly, Japanese Patent Laid-Open No. 2003-233548 discloses the process considering upload traffic but no process considering the process load on the server apparatus side.
Generally, to upload data via a remote access server, the user carries out information registered in the remote access server in advance together with an upload terminal (e.g., digital camera) and accesses the remote access server based on the information. For this reason, upload often fails due to network traffic in the home network rather than upload traffic from the upload terminal to the remote access server.
There is a demand for implementing, in a network, an arrangement for controlling the upload process in accordance with the state in the network.
Japanese Patent Laid-Open No. 2005-100220 discloses an arrangement which performs a process in consideration of the state in the network, that is, the process load on the server apparatus side. However, the storage device serving as the server apparatus of the data transfer destination is often not an advanced high-performance storage device assumed by Japanese Patent Laid-Open No. 2005-100220 but an inexpensive single-function storage device having only medium performance. For this reason, the storage device only increases its process load by executing the control process according to the process load.
Controlling the upload process in consideration of the process load of the storage device is preferably implemented by any device in the network other than the storage device.
It is also preferable to not only control the upload process based on the process load on the storage device side but also control the whole process for the storage device while monitoring the state in the network.